title: pH- and redox-responsive poly(ethylene glycol) and cholesterol-conjugated poly(amido amine)s based micelles for controlled drug delivery.
abstract: An optimized condition is identified to prepare linear poly(amido amine)s via Michael Addition polymerization of trifunctional amine, 4-(aminomethyl)piperidine (AMPD), with an equimolar diacrylamide, N,N-cystaminebis(acrylamide) (BAC). Poly(ethylene glycol) (PEG) and cholesterol (CE) are conjugated to linear poly(BAC-AMPD) through the reactions with the secondary amino groups in the backbone, respectively, to form poly(BAC-AMPD)-g-PEG-g-CE. The chemical structures of poly(BAC-AMPD) and poly(BAC-AMPD)-g-PEG-g-CE are characterized using NMR and gel permeation chromatography (GPC). Transmission electron microscopy (TEM), dynamic light scattering (DLS) and (1)H NMR results show that micelles with PEG shells and hydrophobic cores composed of poly(BAC-AMPD) and CE are formed via self-assembly of poly(BAC-AMPD)-g-PEG-g-CE in aqueous solution, and the micelles of poly(BAC-AMPD)-g-PEG-g-CE can be degraded by the presence of L-dithiothreitol and show a limited cytotoxicity in vitro. The anti-cancer drug, doxorubicin (DOX), can be loaded into the micelles. The DOX loaded micelles of poly(BAC-AMPD)-g-PEG-g-CE show pH- and redox-responsive drug release and redox-induced formation of aggregates, and it is shown that the DOX loaded micelles can deliver DOX into cells and show a higher efficacy in killing cancer cells than free drug.
authors.affiliation: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, 117602, Singapore; Department of Bioengineering, National University of Singapore, 9 Engineering Drive 1, Block EA #03-12, 117576, Singapore.
authors.forename: Weiren
authors.initials: W
authors.lastname: Cheng
authors.forename: Jatin N
authors.initials: JN
authors.lastname: Kumar
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Ye
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000903:Antibiotics, Antineoplastic / Q000737:chemistry / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002784:Cholesterol / Q000737:chemistry*; D003692:Delayed-Action Preparations; D004317:Doxorubicin / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D010084:Oxidation-Reduction; D010316:Particle Size; D011073:Polyamines / Q000138:chemical synthesis* / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000737:chemistry*
chemical_list: D000178:Acrylamides; D000903:Antibiotics, Antineoplastic; D003692:Delayed-Action Preparations; D008823:Micelles; C531249:Poly(amidoamine); D011073:Polyamines; D011092:Polyethylene Glycols; D004317:Doxorubicin; D002784:Cholesterol
keywords: drug delivery systems; poly(amido amine)s; redox polymers; self-assembly; stimuli-responsive polymers